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    <title>Document</title>
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<body>
    <script>
      class A{
        constructor() {
            this.e = []
        }
        a() {
            function fn() {
                console.log(this, 'this');
            }
            this.e.push(fn)
        }
        b() {
            // this.a()
           console.log(this,11111);
           this.e.forEach(item => {
            // console.log(this, 123456);
            function f() {
                console.log(this,123);
            }
            f()
            item()
           })
        }
      }
      let a = new A()
      a.a()
      a.b()
    </script>
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